generic sys_compat_rt_sigaction()

Again, protected by a temporary config symbol (GENERIC_COMPAT_RT_SIGACTION);
will be gone by the end of series.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

3 files changed, 76 insertions, 0 deletions

diff --git a/arch/Kconfig b/arch/Kconfig
index 6b1df95ffefc..3b4a416fc448 100644
--- a/arch/Kconfig
+++ b/arch/Kconfig
@@ -368,6 +368,9 @@ config GENERIC_COMPAT_RT_SIGPENDING
 config GENERIC_COMPAT_RT_SIGQUEUEINFO
         bool
 
+config GENERIC_COMPAT_RT_SIGACTION
+        bool
+
 #
 # ABI hall of shame
 #
diff --git a/include/linux/compat.h b/include/linux/compat.h
index bbee15ef3ae9..0d53ab4f79c5 100644
--- a/include/linux/compat.h
+++ b/include/linux/compat.h
@@ -142,6 +142,22 @@ typedef struct {
         compat_sigset_word      sig[_COMPAT_NSIG_WORDS];
 } compat_sigset_t;
 
+#ifdef CONFIG_GENERIC_COMPAT_RT_SIGACTION
+struct compat_sigaction {
+#ifndef __ARCH_HAS_ODD_SIGACTION
+        compat_uptr_t                   sa_handler;
+        compat_ulong_t                  sa_flags;
+#else
+        compat_ulong_t                  sa_flags;
+        compat_uptr_t                   sa_handler;
+#endif
+#ifdef __ARCH_HAS_SA_RESTORER
+        compat_uptr_t                   sa_restorer;
+#endif
+        compat_sigset_t                 sa_mask __packed;
+};
+#endif
+
 /*
  * These functions operate strictly on struct compat_time*
  */
@@ -602,6 +618,14 @@ asmlinkage long compat_sys_rt_sigprocmask(int how, compat_sigset_t __user *set,
 asmlinkage long compat_sys_rt_sigpending(compat_sigset_t __user *uset,
                                          compat_size_t sigsetsize);
 #endif
+#ifndef CONFIG_ODD_RT_SIGACTION
+#ifdef CONFIG_GENERIC_COMPAT_RT_SIGACTION
+asmlinkage long compat_sys_rt_sigaction(int,
+                                 const struct compat_sigaction __user *,
+                                 struct compat_sigaction __user *,
+                                 compat_size_t);
+#endif
+#endif
 #ifdef CONFIG_GENERIC_COMPAT_RT_SIGQUEUEINFO
 asmlinkage long compat_sys_rt_sigqueueinfo(compat_pid_t pid, int sig,
                                 struct compat_siginfo __user *uinfo);
diff --git a/kernel/signal.c b/kernel/signal.c
index 5a4aed1244fb..f3665f3de660 100644
--- a/kernel/signal.c
+++ b/kernel/signal.c
@@ -3358,6 +3358,55 @@ SYSCALL_DEFINE4(rt_sigaction, int, sig,
 out:
         return ret;
 }
+#ifdef CONFIG_COMPAT
+#ifdef CONFIG_GENERIC_COMPAT_RT_SIGACTION
+COMPAT_SYSCALL_DEFINE4(rt_sigaction, int, sig,
+                const struct compat_sigaction __user *, act,
+                struct compat_sigaction __user *, oact,
+                compat_size_t, sigsetsize)
+{
+        struct k_sigaction new_ka, old_ka;
+        compat_sigset_t mask;
+#ifdef __ARCH_HAS_SA_RESTORER
+        compat_uptr_t restorer;
+#endif
+        int ret;
+
+        /* XXX: Don't preclude handling different sized sigset_t's.  */
+        if (sigsetsize != sizeof(compat_sigset_t))
+                return -EINVAL;
+
+        if (act) {
+                compat_uptr_t handler;
+                ret = get_user(handler, &act->sa_handler);
+                new_ka.sa.sa_handler = compat_ptr(handler);
+#ifdef __ARCH_HAS_SA_RESTORER
+                ret |= get_user(restorer, &act->sa_restorer);
+                new_ka.sa.sa_restorer = compat_ptr(restorer);
+#endif
+                ret |= copy_from_user(&mask, &act->sa_mask, sizeof(mask));
+                ret |= __get_user(new_ka.sa.sa_flags, &act->sa_flags);
+                if (ret)
+                        return -EFAULT;
+                sigset_from_compat(&new_ka.sa.sa_mask, &mask);
+        }
+
+        ret = do_sigaction(sig, act ? &new_ka : NULL, oact ? &old_ka : NULL);
+        if (!ret && oact) {
+                sigset_to_compat(&mask, &old_ka.sa.sa_mask);
+                ret = put_user(ptr_to_compat(old_ka.sa.sa_handler), 
+                               &oact->sa_handler);
+                ret |= copy_to_user(&oact->sa_mask, &mask, sizeof(mask));
+                ret |= __put_user(old_ka.sa.sa_flags, &oact->sa_flags);
+#ifdef __ARCH_HAS_SA_RESTORER
+                ret |= put_user(ptr_to_compat(old_ka.sa.sa_restorer),
+                                &oact->sa_restorer);
+#endif
+        }
+        return ret;
+}
+#endif
+#endif
 #endif /* !CONFIG_ODD_RT_SIGACTION */
 
 #ifdef __ARCH_WANT_SYS_SGETMASK